conditional kludge for byte swapping -- quiet cmu-stanford mafia

SCCS-vsn: sys/vax/if/if_en.c 4.81

diff --git a/usr/src/sys/vax/if/if_en.c b/usr/src/sys/vax/if/if_en.c
index 098378b..f439693 100644 (file)
--- a/usr/src/sys/vax/if/if_en.c
+++ b/usr/src/sys/vax/if/if_en.c
@@ -46,6 +46,14 @@ struct       uba_driver endriver =
 
 int    eninit(),enoutput(),enreset(),enioctl();
 
 
 int    eninit(),enoutput(),enreset(),enioctl();
 

+#ifdef notdef
+/*
+ * If you need to byte swap IP's in the system, define
+ * this and do a SIOCSIFFLAGS at boot time.
+ */
+#define        ENF_SWABIPS     0x100
+#endif
+

 /*
  * Ethernet software status per interface.
  *
 /*
  * Ethernet software status per interface.
  *


@@ -209,6 +217,24 @@ enstart(dev)
        }
        dest = mtod(m, struct en_header *)->en_dhost;
        es->es_olen = if_wubaput(&es->es_ifuba, m);
        }
        dest = mtod(m, struct en_header *)->en_dhost;
        es->es_olen = if_wubaput(&es->es_ifuba, m);

+#ifdef ENF_SWABIPS
+       /*
+        * The Xerox interface does word at a time DMA, so
+        * someone must do byte swapping of user data if high
+        * and low ender machines are to communicate.  It doesn't
+        * belong here, but certain people depend on it, so...
+        *
+        * Should swab everybody, but this is a kludge anyway.
+        */
+       if (es->es_if.if_flags & ENF_SWABIPS) {
+               register struct en_header *en;
+
+               en = (struct en_header *)es->es_ifuba.ifu_w.ifrw_addr;
+               if (en->en_type == ENTYPE_IP)
+                       enswab((caddr_t)(en + 1), (caddr_t)(en + 1),
+                           es->es_olen - sizeof (struct en_header) + 1);
+       }
+#endif

 
        /*
         * Ethernet cannot take back-to-back packets (no
 
        /*
         * Ethernet cannot take back-to-back packets (no


@@ -378,6 +404,10 @@ enrint(unit)
                off = 0;
        if (len == 0)
                goto setup;
                off = 0;
        if (len == 0)
                goto setup;

+#ifdef ENF_SWABIPS
+       if (es->es_if.if_flags & ENF_SWABIPS && en->en_type == ENTYPE_IP)
+               enswab((caddr_t)(en + 1), (caddr_t)(en + 1), len);
+#endif

        /*
         * Pull packet off interface.  Off is nonzero if packet
         * has trailing header; if_rubaget will then force this header
        /*
         * Pull packet off interface.  Off is nonzero if packet
         * has trailing header; if_rubaget will then force this header


@@ -596,3 +626,27 @@ ensetaddr(ifp, sin)
        sin->sin_addr = if_makeaddr(ifp->if_net, INADDR_ANY);
        ifp->if_flags |= IFF_BROADCAST;
 }
        sin->sin_addr = if_makeaddr(ifp->if_net, INADDR_ANY);
        ifp->if_flags |= IFF_BROADCAST;
 }

+
+#ifdef ENF_SWABIPS
+/*
+ * Swab bytes
+ * Jeffrey Mogul, Stanford
+ */
+enswab(from, to, n)
+       register caddr_t *from, *to;
+       register int n;
+{
+       register unsigned long temp;
+       
+       n >>= 1; n++;
+#define        STEP    temp = *from++,*to++ = *from++,*to++ = temp
+       /* round to multiple of 8 */
+       while ((--n) & 07)
+               STEP;
+       n >>= 3;
+       while (--n >= 0) {
+               STEP; STEP; STEP; STEP;
+               STEP; STEP; STEP; STEP;
+       }
+}
+#endif